Filter cap assembly



Nov. 23, 1965 LA VERN R. TIETZ FILTER CAP AS SEMBLY Filed Dec. 5. 1961INVENTOR- A )49777 7'7 3,218,785 FILTER CAP ASSEMBLY La Vern R. Tietz,Racine, Wis, assignor to Walker Manufacturing Company, Racine, Wis, acorporation of Delaware Filed Dec. 5, 1961, Ser. No. 157,123 4 (Ilaims.(ill. 55-543) This invention relates to breather caps and similar typesof gas transmitting devices and particularly concerns an improved typeof breather cap shell and filter element contained therein findingspecial utility for use as a crankcase breather cap for internalcombustion engines.

Heretofore crankcase breather caps have been provided with various typesof air filtering means which become clogged with oil and dirt andthereby lose considerable effectiveness for allowing proper breathing ofthe crankcase which is necessary for etficient operation of the engine.These breather caps have in the past been cleaned by dipping the capinto a solvent in an attempt to dissolve the oil and dirt from thefiltering material held therein. This cleaning process is of coursetime-consuming and requires much agitation of the cap in order todissolve significant portions of the clogging materials therefrom.

The present invention is characterized by a breather cap havingseparable housing portions containing a disposable paper-type of filterelement. The cap housing and paper element are specifically designed sothat they can be made so cheaply that the element may be economicallydisposed of and replaced or cleaned if so desired. Since the element maybe removed from the cap housing, the cleaning thereof can be much moreefficiently accomplished than heretofore possible.

The main objects of the invention are: to provide a breather cap havingseparable housing sections and a separate filter element; to provideseparable housing sections for a breather cap which are so constructedas to be readily locked or separated by simple manual manipulation; toprovide a filter element with integral sealing means on the ends thereofengageable with specially formed inner portions of the cap sections toprovide positive sealing therewith; to provide the breather cap sectionswith such structure that they may be readily molded from plastic withoutrequiring intricate molding apparatus; to provide cooperating structureon the housing sections and on the filter element which provides aspringtype action tending to positively lock the sections together; andto provide bayonet-type locking means on the housing sections to allowlocking of the sections together and separation thereof by simplemanipulation of the sections relative to each other.

Further objects, advantages and novel features of the invention willbecome apparent from the following description taken in conjunction withthe drawings wherein:

FIGURE 1 is a top View of the breather cap assembly with portions brokenaway;

FIG. 2 is an enlarged longitudinal sectional View taken along the line22 of FIG. 1;

FIG. 3 is a sectional View taken along the line 33 of FIG. 1;

FIG. 4 is a plan view of the locking structure of the cap sections indisassembled array looking from the inside of the sections; and

FIG. 5 is a sectional View taken along the line 55 of FIG. 2.

FIG. 6 is an enlarged, fragmentary, sectional view of the bottom portionof the upper cap section with the lower cap section removed.

In the drawings:

A breather cap and filter assembly 10 comprises a housing consisting ofan upper section 12 and a lower section 14 which form a cavity-16therebetween containing a pleated paper-type of filter element 18.Sections 12 and 14 are preferably molded from suitable plastic materialsuch as nylon which material must be relatively strong and resistant todeterioration by oil fumes and other chemicals commonly incurred withinternal combustion engines. They are designed to be made from simplemolds having only axially extending core pins.

Section 12 has a cup shape and is provided with a slanting bottom 20 andan angularly directed inner peripheral surface 22 intermediate bottom 20and the side wall 24. The outer edge portion of Wall 24 is provided witha ring-shaped rim 28 having a slight chamfer 30 on the inner edgethereof. A plurality of pockets 32 are circumferentially spaced in thetrim 28 and are each defined by a wall 34 and a bottom 36 which isoffset to provide entry grooves 40 for the pockets. The bottom 36 ofeach pocket is formed with a projection 42 providing a shoulder 44. Thesurface 46 in the pocket forms another shoulder adjacent to shoulder 44.Pocket 32 is not provided with an inside wall and opens into the cavity16.

Lower section 14 is formed to provide a bottom portion 50 having aninner annular shoulder 52, a plurality of circumferentially spaced gasports 54, an upstanding side wall 56, and inner walls 58 and 59providing a pipereceiving socket 60. Wall 59 has a plurality ofbreathing ports 64 therein and is provided with a pair of rivettypeprojections 66 passing through apertures 68 in a metal spring member 70and headed over by any suitable plastic fusion technique at 72 to firmlysecure the spring 70 thereto. The walls 58 and 59 may be formed withintegrally molded strengthening ribs 74 positioned as desired thereon.Wall 58 is slightly tapered and provides the socket 66 with an entry end76 slightly larger than the inner portion 78 so that a breather pipe 80will be frictionally received by the socket 60 and clamped between thesocket wall 58 and the spring 70 to retain the housing section 14 firmlythereon. The wall 56 of section 14 is provided at its rim 82 with aplurality of circumferentially spaced radially extending lugs 84providing shoulders 86 on the bottoms thereof adapted to engage theshoulders 46 on the section 12. The edge portions 88 of the lugs 84engage the inner edges 44 of the projections 42 when the lugs are intheir locked position within the pocket 32.

The filter element 18 may be of many well known types, for example, thepleated paper type filter. The bottom end 89 of the filter element orcartridge 18 has a resilient plastic material 99 such as a vinylplastisol molded thereon and the top 91 of the cartridge has anotherresilient plastic piece 92 molded thereon and having an overhangingperipheral portion 94 which in its normal undeformed position extends inabout the same plane as the rest of piece 92. The cartridge is properlylocated on section 14 by means of the annular shoulder 52.

In assembling the cap sections 12 and 14 and the filter element 18, theelement as aforesaid is properly located in the section 14 and thesection 12 is then placed over the top of the filter element and ispressed downwardly thereover to deform the peripheral portion 94 of theseal 92 and cause the rim 82 to slide under the chamfered portion 30 ofthe rim 28 to nest rim 82 therein. Simultaneously the chamfered portion98 of the lugs 84 slide into the grooves 40 until the rim 82 abuts thelower edge 100 of section 12. Section 12 is then rotated in a clockwisedirection to move the projections 42 underneath the lugs 84 until theshoulders 86 of the lugs are properly positioned directly over theshoulders 46. The section 12 is then released and the resilient caps and92 and especially the resilient portion 94 cause the section 12 tospring upwardly to engage lugs 84 with shoulders 44 and 46. It is seenthat the resilient portion 94 allows the vertical distance between therims 82 and 100 to be taken up during the assembly of the cap sectionswithout losing any of the sealing effect of the resilient caps 89 and92. The housing sections are disassembled by reversing thismanipulation. I

The walls 24 and 56 of sections 12 and 14 respectively are formed withslight outward tapers as are the inside and outside of walls 34 of thepockets 32 so that these sections may be readily removed from theplastic mold.

During engine operation air or fumes may be readily transferred betweenthe atmosphere and the crankcase across element 18 by passage throughthe ports 54 and 64 and also through the pockets 32. The location ofports 54 allows any large size or heavy particles of dust entering thebreather cap from the atmosphere to drop back out of the cap and therebyprevent a serious buildup of any dust or other contaminant in the cap.Moreover, the location of these ports causes the air flow into thebreather cap to pass through the entire height of the cartridge ratherthan through a limited portion thereof such as might occur if theseports were located near the top of the cap. In this manner the entirecartridge is utilized to its fullest advantage.

It is readily seen, therefore, that the present invention provides abreather cap which is easy to assemble and disassemble for replacementor cleaning of a cartridge, and also provides a cap having extremelysimple construction so that it may be economically produced.

While it will be apparent that the embodiment of the inventionhereindisclosed is well calculated to fulfill the objects of theinvention, it will be appreciated that the invention is susceptible tomodification, variation and change without departing from the properscope or fair meaning of the subjoined claims.

What is claimed is:

1. In a filter cap assembly for a transmission breather pipe, a filterhousing comprising first and second generally cup-shaped shell sectionsdefining a filtering cavity, said first shell section having anangularly extending annular face portion on one end thereof and aplurality of circumferentially spaced pockets formed around the outerperiphery thereof, said second shell section having a central recessedpipe-receiving portion and a plurality of circumferentially spacedradially extending lugs formed around the outer periphery thereof andadapted to be inserted within said pockets, a pleated paper filterelement in said cavity, said second shell section having a plurality ofair ports spaced radially inward and outward from said filter element,and a pair of resilient annular rings, one of which is interposedbetween said filter element and said first shell section and the otherof which is interposed between said filter element and said second shellsection, said annular face portion on said first shell section beingoperable to engage the adjacent of said resilient annular rings tomaintain said lugs within said pockets to preclude the separation ofsaid first and said second shell sections.

2. In a filter cap assembly, a pair of molded shell sections havinginterengageable means on their adjacent edges, one of said sectionshaving a central recess formed therein for receiving one end of atransmission breather pipe, means including friction means in saidrecess for engaging said breather piper to secure said filter capassembly thereto, said friction means including a tapered surface formedaround said recess for engaging the outer periphery of the end of atransmission breather pipe and spring means on one of said shellsections adapted to frictionally engage the inner periphery of thebreather pipe, a filter element within said shell sections, andresilient means interjacent at least one of said shell sections and saidfilter element operable to resiliently maintain said interengageablemeans secured together.

3. In a filter cap assembly for a transmission breather pipe, a filterhousing comprising first and second generally cup-shaped shell sectionsdefining a filter cavity therebetween, each of said shell sections beingfabricated of a molded plastic material, said first shell section havingan angularly extending annular face portion on one end thereof and aplurality of circumferentially spaced and radially extending shoulderportions on the outer periphery thereof, said second shell sectionhaving a central recessed breather pipe receiving annulus and aplurality of circumferentially spaced radially extending shoulderportions on the outer periphery thereof, said shoulder portions on eachof said first and second shell sections comprising a bayonet typelocking device, a pleated paper filter element in said filtering cavity,said second shell section having a plurality of air ports spacedradially inward and outward from said filter element, friction means onone of said shell sections for engaging the breather pipe to secure thecap thereto, said friction means including a tapered surface formedaround said annulus for engaging the outer periphery of the breatherpipe and spring means on said one shell section adapted to frictionallyengage the inner periphery of the breather pipe, and a pair of resilientannular rings disposed one interjacent each of said shell sections andthe adjacent end of said filter element, said annular face portion onsaid first shell section being adapted to engage the adjacent of saidresilient annular rings to resiliently maintain said shoulder portionson said outer peripheries of said first and second shell sectionsconnected together.

4. In a filter cap assembly for a transmission breather pipe, first andsecond shell sections forming a filtering cavity, said first shellsection having a ring-shaped rim portion defining a plurality ofcircumferentially spaced pockets each of which defines a retainingshoulder portion, said second shell section including a plurality ofcircumferentially spaced lugs each of which is formed with a retainingshoulder portion, said shell sections adapted to be detachably securedto one another by inserting each of said lugs within one of saidpockets, a filter element in said cavity, a resilient annular end capcompressed between one end of said filter element and the adjacent ofsaid shell sections urging said shell sections axially apart whereby totightly engage said shoulder portions of said pockets and said lugs, andfriction means on one of said shell sections for engaging the breatherpipe to secure the cap thereto, said friction means including a taperedannular recess in one of said shell sections adapted to engage the outerperiphery of the end of the breather pipe and spring means on said oneshell section adapted to frictionally engage the inner periphery of theend of the breather pipe.

References Cited by the Examiner UNITED STATES PATENTS 1,398,685 11/1921Gordon. 1,470,579 10/1923 Rohdiek. 2,675,886 4/1954 McMullen 555072,805,695 9/1957 Barnes 2204O 2,816,795 12/1957 Brucker 22040 XR2,848,065 7/1958 Sebok 55-498 2,988,170 6/1961 Pritchard 55502 2,996,1458/1961 Thornburgh 55498 3,104,966 9/1963 Goulet et a1. 55521 FOREIGNPATENTS 602,927 3/ 1960 Italy.

HARRY B. THORNTON, Primary Examiner,

1. IN A FILTER CAP ASSEMBLY FOR A TRANSMISSION BREATHER PIPE, A FILTERHOUSING COMPRISING FIRST AND SECOND GENERALLY CUP-SHAPED SHELL SECTIONSDEFINING A FILTERING CAVITY, SAID FIRST SHELL SECTION HAVING ANANGULARLY EXTENDING ANNULAR FACE PORTION ON ONE END THEREOF AND APLURALITY OF CIRCUMFERENTIALLY SPACED POCKETS FORMED AROUND THE OUTERPERIPHERY THEREOF, SAID SECOND SHELL SECTION HAVING A CENTRAL RECESSEDPIPE-RECEIVING PORTION AND A PLURALITY OF CIRCUMFERENTIALLY SPACEDRADIALLY EXTENDING LUGS FORMED AROUND THE OUTER PERIPHERY THEREOF ANDADAPTED TO BE INSERTED WITHIN SAID POCKETS, A PLEATED PAPER FILTERELEMENT IN SAID CAVITY, SAID SECOND SHELL SECTION HAVING A PLURALITY OFAIR PORTS SPACED RADIALLY INWARD AND OUTWARD FROM SAID FILTER ELEMENT,AND A PAIR OF RESILIENT ANNULAR RINGS, ONE OF WHICH IS INTERPOSEDBETWEEN SAID FILTER ELEMENT AND SAID FIRST SHELL SECTION AND THE OTHEROF WHICH IS INTERPOSED BETWEEN SAID FILTER ELEMENT AND SAID SECOND SHELLSECTION, SAID ANNULAR FACE PORTION ON SAID FIRST SHELL SECTION BEINGOPERABLE TO ENGAGE THE ADJACENT OF SAID RESILIENT ANNULAR RINGS TOMAINTAIN SAID LUGS WITHIN SAID POCKETS TO PRECLUDE THE SEPARATION OFSAID FIRST AND SAID SECOND SHELL SECTIONS.